Soaps have been utilized for years to remove soil from surfaces. Various processes have been used to produce soap. Generally, the two most preferred starting materials are triglycerides which are saponified into soap and free-fatty acids which are neutralized into soaps. Saponification of the triglyceride is usually performed in an open kettle at a temperature of from about 215-220.degree. F. over a long period of time, several hours. Alternatively, the saponification is carried out in a continuous closed systems at super atmospheric pressure and a temperature of about 250.degree. F. Fatty acid neutralization is usually not carried out in an open kettle because of oxidation problems. It is usually performed in a closed system at atmospheric pressure and a temperature of about 195.degree. F.
The invention of this application allows for both saponification and neutralization to occur simultaneously at a temperature not generally achievable by saponification alone. This invention brings about significant cost savings, primarily realized from three avenues. Firstly, the price differential between the neutral oil or fat as opposed to the total use of fatty acids is substantial. Secondly, the in situ formation of glycerin negates the need to purchase glycerin and add such glycerin to soap made by neutralization alone. Thirdly, the mixed charge of triglyceride and fat allows the reaction to proceed at a lower temperature than is normally required for complete saponification of a total triglyceride feed charge. This provides for lower energy input as well as an additional cost advantage with respect to equipment purchase price since equipment rated for higher pressures and temperatures is not required.